Conventional clinical examinations are generally performed by detecting the presence and measuring the amount of material in a collected blood specimen. For example, diabetes patients, themselves, frequently-measure their blood sugar level and determine the insulin dosage and food restrictions and amount of exercise based on the measured blood sugar level, as they self-manage their blood sugar. In this way the diabetes patient must measure her blood sugar level several times per day. Since measuring the blood sugar level is normally accomplished by measuring a blood sample collected using a piercing tool, there is some associated physical pain and stress for the patient. From this point of view, a simple examination that is less stressful for the patient and that does not require blood collection is very desirable.
In response to this desire, conventional devices have been disclosed that use a so-called reverse iontophoresis to extract interstitial fluid by means of an electrical current flowing through the skin (for example, U.S. Pat. No. 5,279,543, and International Patent Publication No. 96/00110). In the devices using the reverse iontophoresis method disclosed in these patent publications, interstitial fluid is extracted using two collection media corresponding to a positive electrode and negative electrode.
In the devices using the reverse iontophoresis method disclosed in these patent publications, since interstitial fluid is extracted using two collection media corresponding to a positive electrode and negative electrode, the analyte extracted from living tissue is dispersed in the two collection media. Therefore, a problem arises with regard to the pain and damage to the subject because a relatively large electric current is required to extract to the two collection media the amount of analyte necessary for analysis within a predetermined time.